基本拧紧技术讲解ppt课件.ppt

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1、基本拧紧技术Basic tightening technique,1,2,目的与概要Purpose,掌握以下几个要点，并能与客户就生产中的相关问题进行解释，为客户提供正确的工具和方案作指导内容Content螺纹紧固件thread joint什么是连接件？joint扭矩，摩擦力和夹紧力的关系torque, friction and clamp force关于扭紧的几个基本概念tightening conception抗拉强度和屈服点tensile stress and yield,3,生产过程中的几种装配方法assembly,焊接粘接铆接用螺丝和螺栓拧紧,4,哪种装配方法最普遍？Which on

2、e is most common,焊接粘接铆接用螺丝和螺栓拧紧,?,5,使用螺丝和螺栓拧紧！Advantages with screws and bolts!,设计简单Simplicity of design零部件标准化Standardized装配简单，拆卸方便（可逆）Easy assembly and disassembly效率高High productivity 成本低COST efficient可控（螺栓张力可控）well controlled,!,But why?,什么是连接What is a joint?部件Parts不同的连接Different joint types不同的负载Di

3、fferent loads扭矩、摩擦力和加紧力Torque, friction and clamp force连接类型Joint types 抗拉强度和屈服点Tensile stress and yield point螺栓标记Bolt marking螺栓分级Screw classifications,6,基本拧紧技术Basic tightening technique,连接受到不同的外力The joint is exposed to different external forces,7,什么是连接What is a joint?,螺栓Screw,螺母Nut,连接件Joining parts,

4、这种情况必须避免This must be avoided!,8,The thread creates the clamp force that holds the joint together,Turning the nut or screw stretches the screwThe stretching of the screw clamps the parts togetherThe clamp force in the joint is the target of all tightening,9,10,施加的扭矩The applied torque is measured,夹紧力是

5、我们的目标Clamp forceis our target,夹紧力是我们的目标，但是很难测量，而扭矩很容易测量Clamp force is what we aim at but it is difficult to be measured. Torque is easy to measure and to apply,螺纹紧固件Threaded fasteners - Torque,11,直接测量夹紧力的方法the way to measure clamp force,12,为了拧紧螺栓, 必须施加力以便拧紧螺母/螺丝The applied torque is must,螺纹副摩擦力Frict

6、ion in the threads,夹紧力Clamp Force,螺栓头摩擦力Screw head friction,50%,10%,40%,施加100%扭矩，夹紧力的结果Applied Torque (100%) and resulting Clamp Force,正常情况Normal conditions,扭矩Torque,100 %,14,50 40 10 规则541rule,扭矩,100%,90% 的扭矩用于克服摩擦力,产生夹紧力Clamp Force10%,螺纹副中Friction in the threads40%,螺栓头下摩擦力Screw head friction 50%,夹

7、紧力取决于扭矩和其他因素-摩擦力Clamping force is dependent of torque and other factors mainly friction,Fm= T/ (0.16P + (g * 0.58 * d2) + (Dkm/2) * k) 螺距Pitch螺纹副Thread 螺栓头Head定义DefinitionsFm = 夹紧力clamping forceP = 螺距pitch of threadg = 螺纹副摩擦系数friction value in threadd2 = 螺栓直径diameter boltDkm=螺栓头表面尺寸 size of surface

8、bolt (nut)-headDkm = (dw + dh)/2 k= 螺栓头表面摩擦系数fricition value surface bolt-head,15,16,改变摩擦力 塑料垫圈friction change-plastic washer,螺纹副摩擦力Friction in the threads,夹紧力Clamp Force,螺栓头摩擦力Screw head friction,17,改变摩擦力 加润滑friction change-lubrication,18,扭矩和夹紧力的关系torque and clamp force,螺纹副摩擦力Friction in the thread

9、s,夹紧力Clamp Force,螺栓头摩擦力Screw head friction,19,摩擦力减小会导致.friction decrease,20,改变摩擦力 生锈的螺栓friction change-rusty bolt,21,生锈的螺栓rusty bolt,螺纹副摩擦力Friction in the threads,夹紧力Clamp Force,螺栓头摩擦力Screw head friction,扭矩和夹紧力的关系torque and clamp force,Prevailing torque compensation,Angle / Time,Torque,Prevailingtor

10、que,Prevailingtorquecompensation,Target torque,扭矩Torque (Nm),角度Angle (degrees),啮合点Snug level,硬连接Hard Joint拧紧到目标扭矩角度小于30Tightening angle below 30,目标Target,30,硬连接Hard joint,软连接Soft Joint拧紧到目标扭矩角度小大于720 Tightening angle above 720,over 720,软连接Soft joint,扭矩Torque (Nm),角度Angle (degrees),啮合点Snug level,目标Ta

11、rget,Real joints,很少连接是硬连接Very few joints are below 30,很少连接是软连接Very few joints are above 720,绝大多数是中性连接Most joints are between 30 and 720为什么这样定义Why do we have these definitions?,硬连接Hard Joint拧紧到目标扭矩角度小于30Tightening angle below 30,软连接Soft Joint拧紧到目标扭矩角度小大于720 Tightening angle above 720,过拧紧Overshoot and

12、 Mean shift,26,Target,中间飘移Mean Shift,T,Angle ( ),过拧紧Overshoot,贴合面Snug level,Hard,Soft,抗拉强度和屈服点Tensile strength and yield point,强度Stress,角度Angular displacement,失效Failure,抗拉强度Tensile strength,屈服点Yield point = %抗拉强度of tensile strength(弹性区域的终点 The end point of elastic range),螺栓扭紧过程定义Tightening cycle,螺栓标

13、识The Bolt Marking System,29,ManufacturerFirst figure = 1/100 of min tensile stress (N/mm2)100* 8 = 800 N/mm2 Second figure = relation between tensile stress and yield 0,8 = 80%Multiply the two figures to get the yield point 800* 0,8 = 640 N/mm2,30,螺栓标识The Bolt Marking System,31,螺栓分级Screw quality cla

14、ssification,With torque indications,32,推荐力矩值Recommended torque levels,33,螺栓连接的分级joint classification,34,所需最小的夹紧力必须保证连接件在外力影响下部件仍能结合clamp force最大夹紧力由螺丝/螺栓尺寸和质量，以及相关拧紧设备的精度决定clamp force541原则torque and clamp force,扭矩的最大值和最小值torque,硬连接720 连接的硬度与目标扭紧的设定有关。,按其失效后所产生的后果不同分为三级：普通连接重要连接安全重要连接,螺栓的连接硬度joint hardness classification,螺栓连接的分级joint hardness classification,总结Summary,More Than Productivity,